Conventionally, there has been known a prime mover which is designed to generate a moving power by converting the potential energy of a weight to the kinetic energy of a output shaft.
Patent Document 1 shows one example of such a prime mover. The prime mover shown in Document 1 is designed such that an output shaft employed as a rotatable axis is enabled to rotate by taking advantage of the force to be generated as the weight falls, that the weight thus fell down is then pulled up to an uppermost portion by taking advantage of a spring and a pulley, and that the weight thus pulled up is then caused to fall, thereby enabling the output shaft to continuously rotate.